Fuel burner system



Nam. 28, 3333 H. DHAMQND fi fi FUEL BURNER SYSTEM Filed Dec. 19, 1950 2Sheets-Sheet 1 WIT/1155553: M INVENTOR 175m? Diamond 6%. 0? day; 1 4/ vATTORNEY FUEL BURNER SYS TEE l Filed Dec. 19, 1930 2 Sheets-Sheet 2'ATTORNEY Patented Nov. 28, 1933 PATENT OFFICE roar. BURNER srs'rsu HymenDiamond, Pittsburgh, Pa, aaeignor to Westinghouse Electric &Manufacturing Company, a corporation of Pennsylvania ApplicationDecember 19, 1930 Serial No. 503,386

Claims. (01. 158-28) My invention relates to fuel burners and hasparticular relation to control systems for regulating the activity ofburners.

A fuel-burner-control system, constructed and 6 operated according tothe teachings of the prior art with which I am familiar, ordinarilycomprises a fuel-supply system, including an oil tank and a power-drivendevice for delivering the oil from the tank in atomized condition, anignition 10 system for the atomized fuel and a system of relays wherebythe activity of the fuel-supply apparatus and the ignition device isregulated.

The control systems provided by the earlier prior art are not entirelysatisfactory. The

16 earliest devices depended, for their regulation,

on thermostats, heated by the flame in the furnace and by the fluegases. Thus, the thermostat in the flame actuates a system of relays todeenergize the ignition, while the thermostat 20 in the flue actuates asecond system of relays to transfer the burner system to a permanentlyoperating condition from the temporary condition in which it operatesbefore its capability of operating properly is established.

Control systems of this type have the disadvantage that they arecomparatively slow in response. In an enterprise wherein the apparatushas as much potentiality of doing damage, as in liquid-fuel burners, theproducers can hardly depend upon a slow-acting device for their safetyfeature.

Accordingly, the developments of the later prior art follow an entirelydifferent line of attack upon the problem. In the systems of this asclass, the devices that actuate the control apparatus depend on theionization of the flame, and on the high-frequency effect produced bythe ignition, for their operation.

However, inthis connection, considerable dim- 40 culties have developed.The current through an ionized flame is comparatively small, unlessconsiderable voltage is impressed/across the flame. Theriskkandfithednconvenience involved, in the util ization ofcomparatively high potentials for any considerable length of time,renders a sys-- tem, depending directly upon the ionization current,almost as undesirable as a system depending upon.thermostats.

An attempt has been made to improve the regulation systems of this typeby utilizing the ignition spark for checking the condition of the fuelin the burner. However, this method, of

checking the condition of the furnace, has proved unsatisfactory byreason of the deleterious effect that the arc, produced in theflame, hason the the condition of the flame after it has once been ignited. Such asituation is highly undesirable, since the flame in a furnace may bechoked out after having burned for a certain period of time. In such anemergency, the temporary spark flame-checking device is useless.

Recently, a more satisfactory system has been developed of a typewherein the ionization current in the flame is utilized to operate anelectricdischarge relay. The conductive path of the flame provides aleak for the blocki..g current that collects on the grid of agrid-controlled electric-discharge tube, and, consequently, enables 'thetube to become energized and to energize, in turn, the necessary relays.

The only disadvantage of systems of this type resides in the fact thatthe tube has a limited life, and, while it will run for a considerablelength of time, it will eventually become unresponsive to the conditionof the flame.

It is, accordingly, an object of my invention, to provide afuel-burner-control system of a type incorporating an electric-dischargedevice, wherein the device is so related to the remainder of theapparatus as to be active only when the fuel burner is being started.

An additional object of my invention is to provide, for a fuel burner, aflame-checking device that shall be active only during the period ofignition of the flame.

A further object of my invention is to provide, for a fuel burner of thetype incorporating a fuel-supply system and a fuel ignition system, anelectric-discharge device that shall be energized to regulate theactivity of the fuel-ignition system and that shall be deenergized bythe ignition of the fuel in the burner.

Another object of my invention is to provide, for a fuel burner of thetype incorporating a fuel supply device, an ignition device and atimecontrolled device for interrupting the activity of the fuel-supplysystem, an electric-discharge device for regulating the activity of thetime-controlled device. 1 A still further object of my invention is toprovide, for a fuel burner of the type incorporating a power supplysystem for actuating the necessary elements of the burner, such asignition and fuel supply. a time-controlled device for interrupting theactivity of the power-supply system and an electric-discharge devicethat shall be responsive to the condition of the fuel within said burnerfor regulating the activity of the time-controlled device.

More specifically stated, it is an object of my invention to provide afuel-burner-control system, of the type incorporating anelectric-discharge device adapted to check the presence of the flame,wherein the device shall be energized for initiating the flame, butshall be deenergized by the ionized condition thereof.

According to a preferred embodiment of my invention, I provide afuel-burner system, of a type incorporating an electric-dischargedevice, wherein the device is rendered active simultaneously with thefuel-supply device and, in turn, causes the ignition device to becomeactive. The electric-discharge device is subsequently rendered inactiveby the ionization of the flame produced by the ignited fuel and, inturn, renders the ignition device inactive.

The power supply, for the excitation of the electric-discharge device,for the fuel-supply sys-, tem and for the ignition device, is deliveredthrough 'a transformer, the primary of which is in series with abi-metal contactor heated from a coil that is in series with theprincipal electrodes of the electric-discharge device. The bimetal is,consequently, heated as long as the electric-discharge device is in anenergized condition. If the fuel should not be ignited, the bimetalwould eventually be heated to such point as to open the primary circuit,and hence, to interrupt the activity of the elements of the system. Onthe other hand, when the electric-discharge device becomes deenergizedby reason of the flame ionization, the current through the heating coilof the bi-metal is discontinued, and the elements of the system continuein their active condition for a time regulated by the heat supply thatis desired.

In a modification of my invention, the fuelsupply system is notenergized directly from the primary of the power-transmissiontransformer but is in a circuit that can only be closed when theignition spark is in suitable condition for igniting the fuel. It isthus seen that the latter system incorporates, not only a flame-checkingdevice, but also an ignition-checking device.

The novel features that I consider characteristic of my invention areset forth with particularity in the appended claims. The inventionitself, however, both as to its organization and its method ofoperation, together with additional objects and advantages thereof, willbest be understood from the following description of speciflcembodiments, when read in connection with the accompanying drawings, inwhich:

Figure 1 is a diagrammatic view illustrating a preferred embodiment ofmy invention, and

Fig. 21s a diagrammatic view illustrating a modified embodiment of myinvention.

The apparatus shown in Fig. 1 comprises a section of a room 1 of a housewherein a temperature-responsive thermostat 5 is disposed, and a sectionof the basement 7 of the house 1 wherein a heating equipment 9 islocated.

The thermostat 5 is so regulated that when the temperature of the room 1attains a predetermined lower limit, its movable element 11 engages afixed contact 13 to close a circuit from one power-supply bus line 15,through a lead 17, to the fixed contact 13 of the thermostat 5, throughthe movable bimetallic element 11 of the thermostat 5, another lead 19,the bimetal 21 of a time-delay contactor 23, the primary 25 of atransformer 27, adapted to impress a voltage between the principalelectrodes 29 and 31 of a grid-controlled electric-discharge device 33,the primary coil 35 of an ignition transformer 37 and the primary coil39 of a transformer 41 that supplies power to a motor 43, to theremaining power-supply bus line 44. This circuit is termed the primarycircuit 65.

The secondary coil 47 of the transformer 27 that supplies the power foroperating the electrio-discharge tube 33 is connected to the anode 29 ofthe tube through the heating coil 49 of the time-delay bimetal contactor23, and to the cathode 31 of the tube 33 through the exciting coil 51 ofa relay 53, equipped with a movable contactor 55 that is adapted toclose the ignition circuit 57.

The anode 29 of the discharge device 33 is connected to the controlelectrode 59 of the device through an impedance 61, and the cathode 31of the device is connected to the control electrode 59 through a secondimpedance 63. The impedances 61 and 63 are so related in magnitude thatthe tube 33 is energized when the primary circuit 65 is closed by theroom thermostat 5.

The excitation of the tube 33 causes a current to pass through theheating coil 49 of the timedelay contactor 23 and through the excitingcoil 51 of the ignition relay 53. As a result, the ignition isimmediately initiated.

The secondary of the motor circuit 67, on the other hand, is in closedcondition, and the motor 1 is excited by the closing of the primarycircuit 65. In rotating, the motor 43 drives a pressure blower 69 and anoil pump 71 that supply the fuel, in atomized condition, to thecombustion compartment 73 of the burner.

The lead 75, connecting the cathode 31 to the impedance 63 disposedbetween the cathode 31 and the control electrode 59, is grounded, andthe metallic elements of the compartment 73 are grounded in such mannerthat a flame within 1 the compartment provides a leakage path between aflame terminal 77, connected to the control electrode 59 of the electricdischarge device 33, and ground. The leakage path is thus an impedancepath in parallel with the imped- 1 ance 63 connected between the controlelectrode 59 and the cathode 31 of the tube 33.

By reason of the decrease in impedance between the control electrode 59and the cathode 31 of the electric-discharge device 33, engendered 1 bythe ionized path of the flame, the potential between the controlelectrode and the cathode is decreased, and the electric-dischargedevice 33 is deenergized. The heating current, through the coil 49associated with the time-delay con- 1 tactor 23, as well as the excitingcurrent through the ignition relay coil 51, is interrupted, and theignition is, in turn, interrupted.

Under the above conditions, the burner 9 continues to operate until theroom thermostat .5 1 is opened and, in turn, opens the primary circuit65 of the motor 43, by meansof which the fuel is supplied to thefurnace.

On the other hand, if the fuel fails to become ignited, theelectric-discharge tube 33 remains 1 in an energized condition until thecoil 49 associated with the thermostatic time-delay contactor 23 heatsthe movable element 21 thereof to such point that it disengages thecorresponding fixed contact 79, and engages a hook 81, whereby 1itisheldinflxedpositionuntiltheoperator,whoexaminestheconditionofthemmaceand of the ignition, it.

If desirable, the hook 81, whereby the movable element 21 of thetime-delay contactor is engaged,maybeconnectedto asignallampwhichindicates that the contactor has become disengaged. The signal thus,immediately serves notice to the owner of the furnace that it requiresservicing.

'If the flame-in the furnace 9 should become extinguished while thefurnace is running. the electric-discharge tube 33 immediately becomesenergized, and the ignition is excited and remains in such conditionuntil the flame is either reignited or the time-delay contactor 23 opensthe primary circuit 65.

The appaartus shown in Fig. 2 includes the feature of ignition check.

The electric-discharge tube 33, utilized in checking the flame, in thetype of apparatus illustrated in this view, is connected insubstantially the same circuit as the apparatus illustrated in Fig. 1.However, the ignition circuit 83 is excited through the primary 85 of atransformer 87 included in an independent circuit 89 and adapted to beactuated by the excitation of the tube 33. r

The ignition current is electrostatically coupled through the metallicshell 90 to a lead 91 that is connected to a metallic shield 93enveloping a second electric-discharge device 95. The principalelectrodes 97 and 99 of the electric-discharge device 95 are in the formof concentric cylinders, the anode 9'7 being the innermost cylinder. Aseries of condensers is thus formed between the metallic envelope 93 andthe cathode 99 and the anode 9'1.

If the ignition spark has the necessary properties for ignition, ahigh-frequency potential is established between the metallic envelope 93and the anode 97, since the two condensers in series offer a smallimpedance to the passage of a highfrequency current. In such case, theelectricdischarge tube 95 becomes energized, and one exciting coil 103of a relay 101 in series with the principal electrodes 97 and 99 of thetube 95 is energized by the current flowing through the tube. Theexciting current for the relay 101 flows from the anode 9'1 to thecathode 99, through a lead 105, the secondary 107 of a powertransmission transformer 109, the exciting coil 103 of the relay 101 anda lead 111, to the anode 91 of the tube 95.

Preferably the tube 95 should be of the gridcontrolled type and tofacilitate the operation of the ignition-checking device, the controlelectrode 112 of the device 95 is connected to the cathode through animpedancev 114 (preferably a capacitor). The impedance 114 may be soselected that excitation of the device 95 by the field from the spark isfacilitated by reason of the fact that the control electrode 112 is thusmaintained at a potential in the region of but less than the ignitionpotential.

By reason of the excitation of its coil 103, the

, movable element 113 of the relay 101, associated with theelectric-discharge tube 95, engages a plurality of corresponding flxedelements 115 and closes a second circuit from one terminal of thesecondary 119 of a power-on transformer 1'21, excited from the mainline, through a second exciting coil 123 of the relay 101, a lead 125,the windings of the motor 43, whereby the fuel is supplied, a secondlead 127 and the movable contact 113 of the relay 101, to the remainingterminal of the secondary 119.

The motor 43 is, therefore, energized, and fuel is supplied to thechamber '13. when the fuel becomes ignited, the flame-checkingelectric-discharge device 33 is deenergized, and the relay coil 51,associated with the ignition transformer 87, as well as the heating coil49 of the timedelay contactor 23, are opened. The system is now in itspermanent operative condition, and the heating continues until the roomthermostat is opened.

It is well to point out that in the apparatus described above, it ishighly desirable that the device 33 should be of the type that fails (asit will after a comparatively long period of time) while active. Adischarge device which fails while active continues to glow and, inconsequence thereof, an additional convenient feature is added to thesystem, in that the operation of the burner is not rendered permanent ifthe regulating device is defective.

It is to be noted that the auxiliary coil 123, associated with the relay101 that closes the motor circuit, is provided for the purpose ofpreventing the relay 101 from becoming deenergized when the primarycircuit 89 of the ignition transformer 87 is opened.

It is well to point out that, if the spark gap 129 is so wide that aspark is not produced, the ordinary BO-cycle voltage is induced in thecircuit leading to the metallic envelope 93 of the ignitioncheclringelectric-discharge tube 95. The impedance offered to this voltage by thecapacity, comprising the cathode 99 and the anode 9'7 of the tube 95, islarge and the current that flows under the pressure of the voltage isshort-circuited to ground through the secondary 107 of the transformer109, whereby voltage is supplied between the electrodes of thetube andthe exciting coil 103 of the relay 101 that regulates the operation ofthe motor 43. However, since the tube 95 is unenergized in this state,suflicient current does not flow through the coil 103 of the relay 101to close the contactor 115.

Furthermore, it should be noted that, if the spark gap isshort-circuited, the current that is capacitatively induced in the lead91 is comparatively small, and substantially no currentflows in thecircuit associated therewith.

It should be noted that while in the systems i1- lustrated in thedrawings, the transformers 27, 37, 41, 87, 109 and 121 are shown to beof the oneto-one type; the illustration is only symbolical and thetransformers are ordinarily selected to properly suit the purpose forwhich they are to be applied. Thus in the ignition transformers 37 and37, the output voltage is comparatively large and the ratio of turns ofthe secondaries to the primaries are rather large.

It will be apparent also that the particular connection of thetransformers need not be exactly followed. The primaries 25, 35 and 39of the transformers 2'1, 37 and 91inthe apparatus of the type shown inFig. 1 may, for example, be connected in parallel with each other ratherthan in series with each other. The same modification maybe applied withregard to the primaries of the transformers 27, 109 and 121 of theapparatus shown in Fig. 2.

I am well aware that an ordinary Geisler tube is responsive to ahigh-frequency potential in the vicinity thereof., However, it is to benoted that, by experiment, it has been established that a tube,

of the type described hereinabove, has the property of beingconsiderably more reliable and uniform in its operation than is anordinary Geisler tube. If uniformity of operation may be disregarded, aGeisler tube may be substituted for the device described in the presentapplication.

My invention has hereinabove been described as applied to specificsystems, and tubes of a specific type have been illustrated, as utilizedin the systems.

It is well to note that fuel-burner systems of various types areillustrated and described in the literature relating to the subject.These sys tems incorporate modifications to which my invention isapplicable and, when incorporated therein, serves the same purpose as itserves in the apparatus described hereinabove. My invention is, ofcourse, to be regarded as including, within its scope of equivalents,its application to modified fuel-burner systems.

It is, moreover, understood that my improvement may be applied withtubes of other types than the device specifically illustrated in thedescribed embodiments. Such devices, as hotcathode grid-glow tubes,thermionic tubes, and other tubes of like nature, apparently apply.However, it should be remembered that the coldcathode grid-controlledtube serves the purpose.

for which it is intended, in the present embodiment, mostsatisfactorily, and will possibly have a longer life than the othertubes mentioned.

Finally, it is pointed out, that my system, in its simplest form,embodies the feature of incorporating a combined flame-checking andterminal-leakage-checking device. A leakage path between the fiameelectrode and the ground, other than the flame itself, if such exists,provides the necessary shunting impedance which prevents theelectric-discharge tube from operating and from initiating the operationof the ignition.

Although I have shown and described certain specific embodiments of myinvention, I am fully aware that many modifications thereof arepossible. My invention, therefore, is not to be restricted, exceptinsofar as is necessitated by the prior art and by the spirit of theappended claims.

I claim as my invention:

1. In a fuel-burner system of the type including fuelsupply means,fuel-ignition means, a source of supply of energy for operating saidfuelsupply means and said fuel-ignition means, a plural-electrodeelectric-discharge device for initiating the activity of said ignitionmeans when it is energized and means for energizing saidelectricdischarge device, means responsive to said ignition means forinitiating the activity of said fuel-supply means, and means tocooperate with the flame of the fuel delivered by said fuelsupply meansfor interrupting the activity of said electric-discharge device.

2. A control system for apparatus by the activity of which an ionizedregion is produced comprising a plural electrode electric dischargedevice, means for energizing said device, means, to be actuated by saiddevice when it is so energized, to initiate the activity of saidapparatus and means, responsive to the ionization produced when saidapparatus is active, to deenergize said electric discharge device.

3. A control system for apparatus by the activity of which an ionizedregion is produced,

said apparatus incorporating a priming device to initiate the activitythereof, comprising a plural-electrode electric discharge device, meansfor energizing said electric-discharge device, means to be actuated bysaid device when said electric discharge to weavesitissoenergizedtoenergizesaid primingdsvice and thus to initiate theactivity of said apparatus and means, responsive to ionization producedwhen said apparatus is active, for deenergizing deenergize said primingdevice.

4. A control system for apparatus by the activity of which a state ofionization is produced in a region comprising an electric dischargedevice having a control electrode and a plurality of principalelectrodes, a source of supply of power for energizing said device, anim connected between said control-electrode and at least one of saidprincipal electrodes to maintain said control electrode at a potentialsuch that said device becomes energized when power is applied thereto,means, to be actuated by said device when it is energized, forenergizing said apparatus and means for connecting the ionization pathproduced by the activity of said apparatus between 06 said controlelectrode and at least one of said principal electrodes to apply apotential to the control electrode of said device such that said deviceis deenergized when said apparatus is energized.

5. A controlsystem for apparatus by the activity of which a state ofionization is produced in a region comprising an electric dischargedevice having an anode a cathode and a control electrode, a source ofsupply of power for energizing said device, means for impressingpotentials between said control electrode and said anode and cathode ofsaid electric discharge device such that said device becomes energizedwhen power is applied thereto, means, to be actuated by said device whenit is so energized, for energizing said apparatus and means forconnecting the ionization path produced by the activity of saidapparatus between said control electrode-and said cathode to apply apotential to the control electrode of said device such that said deviceis deenergized when said apparatus is energized.

6. In fuel-burner apparatus of the type including fuel-supply means, anelectric discharge device, means for energizing said electric dischargedevice, means to be actuated by said electric discharge device when itis so energized for energizing said fuel-supply means, means forigniting said fuel when it is supplied and means operative by thecombustion of the fuel within said burner to deenergize said electricdischarge device after said fuel has been ignited.

'7. In fuel burner apparatus of the type including fuel-supply means, anelectric discharge device having a control electrode and a plurality ofprincipal electrodes, means for energizing said electric dischargedevice, means, to be actuated by the current transmitted between theprincipal electrodes of said electric discharge device when it is soenergized, for energizing said fuel supply means, means for ignitingsaid fuel when it is supplied and means operative by the combustion ofthe fuel within said burner to impress a potential between the controlelectrode and the principal electrodes of said electric discharge deviceto deenergize said electric discharge device after said fuel has beenignited.

8. In fuel-burner apparatus of the type including fuel-supply means, anelectric discharge device, having a control electrode and a plurality ofprincipal electrodes, means for energizing said electric dischargedevice, means to be actuated by the current transmitted between theprincipal electrodes of said electric discharge device when it is soenergized for energizing said fuelsupply means, means for igniting saidfuel when it is supplied, means operative by the combustion of the fuelwithin said burner to deenergize said electric discharge device aftersaid fuel has been ignited and means for deenergizing said electricdischarge device to deenergize said fuel-supply means if said fuel failsto become ignited within a predetermined interval of time.

9. In fuel-bumer apparatus of the type including fuel-supply means andmeans for igniting the fuel supplied by said fuel-supply means, anelectric discharge device, means for energizing said electric dischargedevice, means to be actuated by said electric discharge device when itis so energized for energizing said ignition means,

means to be actuated by said ignition means when it is energized forenergizing said fuel-supply means and means operative by the combustionof the fuel when it is ignited for deencrgisingsaid electric dischargedevice.

10. In fuel-burner apparatus of the type including fuel-supply means, anelectric discharge device, means for energizing said electric dischargedevice, means to be actuated by said electric discharge device when itis so energized for energizing said fuel-supply means, means formaintaining said fuel supply means energized independently of saidelectric discharge device after it has been energized, means forigniting said fuel when it is supplied and means operative by thecombustion of the fuel within said burner to deenergize said electricdischarge device after said fuel has been ignited.

HYMEN DIAMOND.

